The present invention relates to a locking device for opening and closing the door of a cooking apparatus.
A conventional door locking device is generally provided with a lock mechanism with a hook. The door locking device is mounted inside a door, and the hook is operated by a door handle mounted on the door so as to releasably engage with an engaging hole formed in a cooking (heating) chamber. FIG. 1 shows a door locking device for a microwave oven. Referring to FIG. 1, a movable door handle b is arranged at the front surface of a door a at the free end thereof. A movable hook c is mounted on the rear surface of the door a. The hook c and the door handle b are coupled together by an interlocking mechanism d such as a link incorporated inside the door a. An engaging hole g formed in a locking member f for engaging with the hook c is formed at the front wall of a housing e. Thus, the door handle b may be operated to releasably engage the hook c with the engaging hole g, thereby locking the door a to the housing e and closing a safety switch i. Food in the heating chamber may then be cooked by dielectric heating of microwave energy.
However, in a door locking device adopting the interlocking mechanism d whereby the door handle b is interlocked with the hook c, the structure becomes complex and the number of parts involved increases. Therefore, the overall device becomes costly. Furthermore, since the interlocking mechanism d is arranged inside the door a, extra space is required, imposing a limit on the degree of freedom in designing of the door a. Opening of the door a requires a two-step operation including unlocking and opening the door, and this is liable to result in poor operability. Especially, a microwave oven is provided with an electromagnetically sealed door a adopting the high frequency choke system, for example, so that the composition of the interlocking mechanism d adversely affects the choke system, and degrades the electromagnetic sealing performance.